Currently, an Orthogonal Frequency Division Multiplexing (OFDM) scheme or an Orthogonal Frequency Division Multiple Access (OFDMA) scheme known as useful schemes for high-speed data transmission in wired/wireless channels may transmit data using a plurality of carriers, and more specifically, may convert data inputted in serial into data in parallel, modulate the converted data into a plurality of subcarriers having mutual orthogonality with respect to each of the converted data, that is, sub-channels, and transmit the modulated data.
The above-mentioned OFDM scheme may transmit data while maintaining orthogonality between the plurality of subcarriers, and thus obtaining optimum transmission efficiency at the time of high-speed data transmission, and also obtaining multi-path fading tolerance characteristics and superior frequency efficiency.
Also, the OFDM scheme may superimpose one frequency spectrum over another, and thus reducing interference effects between symbols using a guard zone tolerating frequency selective fading, simply designing a structure of an equalizer in hardware, and tolerating impulse noise.
However, a conventional OFDM system having a single flow type structure may change a magnitude of a fast Fourier transform (FFT) to adjust a transmission speed, or a conventional OFDM system having a parallel flow type structure may parallelize only partially encoded and decoded parts or a Radio Frequency (RF) front-end, each which results in reduction in an operation speed of all hardware in a high speed system.